C++ LPSTORAGE::EnumElements方法代码示例

void ReadStorage(LPSTORAGE pStg)
// reads one storage -- recursive calls for substorages
{
    USES_CONVERSION;
    LPSTORAGE pSubStg = NULL;
    LPSTREAM pStream = NULL;
    LPENUMSTATSTG pEnum = NULL;
    LPMALLOC pMalloc = NULL; // for freeing statstg
    STATSTG statstg;
    ULONG nLength;
    BYTE buffer[101];

    g_nIndent++;
    ::CoGetMalloc(MEMCTX_TASK, &pMalloc); // assumes AfxOleInit
                                          //  was called
    VERIFY(pStg->EnumElements(0, NULL, 0, &pEnum) == S_OK);
    while (pEnum->Next(1, &statstg, NULL) == S_OK) {
      if (statstg.type == STGTY_STORAGE) {
        VERIFY(pStg->OpenStorage(statstg.pwcsName, NULL,
               STGM_READ | STGM_SHARE_EXCLUSIVE,
               NULL, 0, &pSubStg) == S_OK);
        ASSERT(pSubStg != NULL);
        TRACE("%0.*sStorage = %s\n", (g_nIndent - 1) * 4,
              g_szBlanks, OLE2CT(statstg.pwcsName));
        ReadStorage(pSubStg);
        pSubStg->Release();
      }
      else if (statstg.type == STGTY_STREAM) {
        VERIFY(pStg->OpenStream(statstg.pwcsName, NULL,
               STGM_READ | STGM_SHARE_EXCLUSIVE,
               0, &pStream) == S_OK);
        ASSERT(pStream != NULL);
        TRACE("%0.*sStream = %s\n", (g_nIndent - 1) * 4,
               g_szBlanks, OLE2CT(statstg.pwcsName));
        pStream->Read(buffer, 100, &nLength);
        buffer[nLength] = '\0';
        TRACE("%s\n", buffer);
        pStream->Release();
      }
      else {
        ASSERT(FALSE);  // LockBytes?
      }
      pMalloc->Free(statstg.pwcsName); // avoids memory leaks
    }
    pMalloc->Release();
    pEnum->Release();
    g_nIndent--;
}

STDAPI UtDoStreamOperation(LPSTORAGE pstgSrc, LPSTORAGE pstgDst, int iOpCode,
		DWORD grfAllowedStmTypes)
{
	VDATEHEAP();

	HRESULT error; // error status so far
	IEnumSTATSTG FAR* penumStg; // used to enumerate the storage elements
	ULONG celtFetched; // how many storage elements were fetched
	STATSTG statstg;
		
	// get an enumerator over the source storage
	if (error = pstgSrc->EnumElements(NULL, NULL, NULL, &penumStg))
		return error;
	
	// repeat for every storage
	while(penumStg->Next(1, &statstg, &celtFetched) == NOERROR)
	{
		
		// operate on streams that we're interested in
		if (statstg.type == STGTY_STREAM)
		{
			DWORD stmType;
			
			// find the type of the stream
			// REVIEW, we must have constants for these name
			// prefixes!!!
			switch (statstg.pwcsName[0])
			{
			case '\1':
				stmType = STREAMTYPE_CONTROL;
				break;
				
			case '\2':
				stmType = STREAMTYPE_CACHE;
				break;
				
			case '\3':
				stmType = STREAMTYPE_CONTAINER;
				break;
				
			default:
				stmType = (DWORD)STREAMTYPE_OTHER;
			}
			

			// check whether it should be operated upon
			if (stmType & grfAllowedStmTypes)
			{
				switch(iOpCode)
				{
#ifdef LATER                                    
				case OPCODE_COPY:
					pstgDst->DestroyElement(
							statstg.pwcsName);
					error = pstgSrc->MoveElementTo(
							statstg.pwcsName,
							pstgDst,
							statstg.pwcsName,
							STGMOVE_COPY);
					break;

				case OPCODE_MOVE:
					pstgDst->DestroyElement(
							statstg.pwcsName);
					error = pstgSrc->MoveElementTo(
							statstg.pwcsName,
							pstgDst,
							statstg.pwcsName,
							STGMOVE_MOVE);
					break;

				case OPCODE_EXCLUDEFROMCOPY:
					AssertSz(FALSE, "Not yet implemented");
					break;
					
#endif // LATER
				case OPCODE_REMOVE:
					error = pstgSrc->DestroyElement(
							statstg.pwcsName);
					break;
				
				default:
					AssertSz(FALSE, "Invalid opcode");
					break;
				}
			}
		}
		
		// if the enumerator allocated a new name string, get rid of it
		if (statstg.pwcsName)
			PubMemFree(statstg.pwcsName);

		// quit the enumeration loop if we've hit an error
		if (error != NOERROR)
			break;
	}

	// release the enumerator
	penumStg->Release();

//.........这里部分代码省略.........